Duration reproduction under memory pressure: Modeling the roles of visual memory set size in duration encoding and...

Duration estimates are systematically biased toward the mean of recently sampled intervals, a central-tendency effect typically attributed to the integration of sensory evidence with prior expectation. Yet the role of concurrent cognitive demands in shaping these biases has remained largely unexplored. Across five experiments, we investigated how visual working-memory set size influences duration estimation when imposed during encoding, reproduction, or both phases of a duration-reproduction task. Participants reproduced visual intervals while maintaining one, three, or five colors in memory. Increasing memory set size during encoding consistently shortened reproductions and strengthened central-tendency effect, whereas increasing set size during reproduction lengthened reproductions without altering central tendency. To account for these opposing effects, we developed a hierarchical Bayesian model incorporating attention-sharing mechanisms, which captured how increasing set size alters both bias and precision across experimental contexts. The model identifies encoding as the critical locus at which larger set sizes elevate uncertainty and enhances reliance on prior information. Our findings reveal that working-memory demands modulate duration estimation through stage-specific interference and highlight broader implications for magnitude perception under cognitive load.